1. Field of the Invention
The present invention relates to a vehicular air conditioning apparatus mounted in a vehicle for blowing air into a vehicle compartment that has been adjusted in temperature by a cooling means, for thereby adjusting temperature of the vehicle compartment.
2. Description of the Related Art
In a vehicular air conditioning apparatus that is mounted in a vehicle, internal and external air is introduced into a casing by a blower, and after cooled air, which has been cooled by an evaporator that forms a cooling means, and heated air, which has been heated by a heater core that forms a heating means, are mixed together in the casing at a predetermined mixing ratio, the mixed air is blown out from a defroster blow-out port, a face blow-out port, or a foot blow-out port, whereby adjustment of temperature and humidity in the vehicle compartment is carried out.
With this type of vehicular air conditioning apparatus, for example, as disclosed in Japanese Laid-Open Patent Publication No. 05-178068, Japanese Laid-Open Patent Publication No. 06-040236 and Japanese Laid-Open Patent Publication No. 06-191257, it is known to provide a first blower for the purpose of taking in air from the vehicle compartment into the casing, and a second blower for the purpose of taking in external air outside of the vehicle compartment into the casing. In such a vehicular air conditioning apparatus, air that is introduced from an internal air introduction port by rotation of the first blower is heated by a first heat exchanger and then is blown into the vehicle compartment through a first air passage from the face blow-out port or the foot blow-out port. In addition, air that is introduced from an external air introduction port by rotation of the second blower is heated by a second heat exchanger and then is blown into the vehicle compartment through a second air passage from the defroster blow-out port. More specifically, a switching operation is performed such that when air is blown out from the face blow-out port or the foot blow-out port, the first blower is driven and air from the interior of the vehicle is introduced, whereas when air is blown out from the defroster blow-out port, the second blower is rotated and external air is introduced.
Further, in another vehicular air conditioning apparatus having first and second blowers for introducing air, the first blower is arranged facing toward an external air inlet port of a duct, and the second blower is arranged facing toward an interior air inlet port, and together therewith, the first blower includes a switching means, which is capable of switching the air that is introduced to the duct by the first blower between interior air and exterior air.
In addition, the air that is introduced to the duct by the first blower is switched between interior air and exterior air by the switching means, and after the air is mixed with air that is introduced to the duct by the second blower and adjusted in temperature by a heating means and a cooling means so as to provide a desired temperature, the air is blown into a desired region in the vehicle compartment through a face blow-out port, a foot blow-out port, or a defroster blow-out port.
In the aforementioned structure, with the vehicular air conditioning apparatus, for example, as disclosed in Japanese Laid-Open Patent Publication No. 2001-180255, when air is cooled by an evaporator that constitutes the cooling means thereof, water droplets (hereinafter also referred to as condensate water) are generated on surfaces of the evaporator. When such water droplets are left uncontrolled as is, freezing and build-up of ice occurs, thus reducing the effective area of the evaporator, and the heat conversion efficiency of the evaporator is drastically lowered. Consequently, measures have been taken to discharge such water droplets to the exterior.
Recently, in response to demands to increase the vehicle compartment space inside of vehicles, it is desirable to reduce the size and scale of the vehicular air conditioning apparatus, which is mounted in the vehicle.
With respect thereto, with the conventional technique pertaining to the aforementioned Japanese Laid-Open Patent Publication No. 2001-180255, so that condensate water, which is generated at the evaporator, can be discharged to the exterior regardless of changes in the posture of the vehicle during running thereof, a bottom surface of the casing is inclined significantly in a downward direction, such that at all times condensate water is collected toward a water discharge or drainage port provided on the bottom surface of the casing. Notwithstanding, by adopting such a structure, the dimension in the vertical direction on the bottom surface portion of the casing becomes large, and accommodation of the vehicular air conditioning apparatus within the limited space inside the vehicle is problematic. Stated otherwise, configuring the vehicular air conditioning apparatus in this manner runs contradictory to efforts to reduce the size and scale of the vehicular air conditioning apparatus.